Well bore perforating apparatus

ABSTRACT

In the representative embodiment of the present invention disclosed herein, new and improved selectively-operated perforating apparatus is arranged to include two or more enclosed thin-walled tubular carriers carrying a corresponding number of sets of shaped explosive charges which are to be independently actuated for successively perforating a cased well bore at selected depth intervals. To effectively protect the charges in the yet-unfired carriers during the sequential operation of the perforating apparatus, the carriers are tandemly joined by a unique shock-isolating inter-carrier coupler cooperatively arranged for carrying interconnecting wires between the carriers as well as for at least substantially absorbing the longitudinally directed and laterally directed explosive shocks or impacts which are inherently developed by such sequential firing operations.

United States Patent 11 1 1111 3,923,107 Dillard 1 51 Dec. 2, 1975 WELLBORE PERFORATING APPARATUS FOREIGN PATENTS OR APPLICATIONS I751 DillardMagnolia, 360,554 4/1962 Switzerland 285/54 [73] Assignee: SchlumbergerTechnology Corporation, N w Y k, N Y Primary E,\'amine'rDavid H. BrownAttorney, Agent, or Firm-Ernest R. Archambeau, Jr.; {22] Flled: 1974William R. Sherman; Stewart F. Moore [21] Appl. No.: 529,419

1 1 ABSTRACT [52] US. Cl. 175/455; 285/54; 285/235 In the pr n ativeodiment of the present in- [51] Int. cl. E21B 43/11 vention disclosedherein, new and improved selective- [58] Field 61 Search 166/55, 55.1;yp Perforating apparatus is arranged to l75/4.54.6; 174/85, 138 D; 64/11R, 13; clude two or more enclosed thin-walled tubular carri- 403/220,291, 225; 285/49, 114, 223, 224, ers carrying a corresponding number ofsets of shaped 235, 370, 371, 397, 398, 302, 54, 47, DIG, 14 explosivecharges which are to be independently actuated for successivelyperforating a cased well bore at [56] References Cited selected depthintervals. To effectively protect the UNITED STATES PATENTS charges inthe yet-unfired carriers during the sequential operation of theperforating apparatus, the carriers 1 fi ggrzi' c are tandemly joined bya unique shock-isolating inter- 2 620 l65 12/1952 Crickmer 2.1.11 64/11R Came coupler Peratively arranged for carrying 2:75 :022 7/1956Sturgeon I I 285/114 X terconnecting wires between the carriers as wellas for 2,795,398 6/1957 Ragland 1 285/231 X at least substantiallyabsorbing the longitudinally di- 3,036,521 /1962 Owen l75/4.6 rected andlaterally directed explosive shocks or 'im- 3,190,680 6/1965 Maly285/231 X pacts which are inherently developed by such sequen- 3,211.09310/1965 McCullough et al. l75/4.6 tial fi i operaticmg 3,216,751 11/1965Der Mott..... 285/235 x 3.441.093 4/1969 BOOP 175/455 11 Claims. 4Drawing Figures US. Patent Dec. 2, 1975 3,923,107

F/G.7 F/GIZ FIG.3

WELL BORE PERFORATING APPARATUS Present-day completion techniques oftenrequire the perforation of a well at two or more different depthintervals. Very often this must be carried out without removing thesmall-diameter production tubing from the well. To accomplish this, itis customary to tandemly arrange a corresponding number ofsmall-diameter perforating guns into a selectively controlled unitaryassembly and, by means of a typical electrical cable, lower theassembled tool through the production string to the depth interval wherethe first gun is to be operated. Thereafter, the perforator tool isrepositioned and the second gun is operated for perforating theformations at the second depth interval. This procedure is repeateduntil all of the several guns in the perforator tool have been fired.

Those skilled in the art will, of course, appreciate that where each ofthese guns include a number of shaped explosive charges, thesimultaneous detonation of these charges will impose severe shocks andsudden impacts on the entire perforator tool. This problem has beenaccentuated by the recent development of morepowerful charges. Inparticular, where the charges are carried in thin-wall tubular carrierssuch as those shown in US. Pat. No. 3,048,102 and US. Pat. No.3,429,384, these carriers are typically so light that the entireperforator tool will often be driven laterally with considerable forceeach time the charges in one of the carriers in the tool are detonated.

Accordingly, it has been not at all uncommon to find that the operationof the first set of charges in a tandem assembly of such light-weightcarriers has damaged one or more of the unexpended shaped charges in theadjacent carriers in the perforator tool. For example, as shown in FIG.2 of the aforementioned US. Pat. No. 3,429,384, there is ordinarily aminimal clearance space between the internal carrier wall and theforward and rearward portions of the shaped charges. Thus, the suddenimpact or shock developed upon firing of one set of charges will rapidlydrive or shift an adjacent carrier of this type laterally in relation tothe several shaped charges enclosed therein since the charges aretypically supported by only a thin, generally flexible metal strip.Forceful inertial movements of this nature are known to be particularlyresponsible for damage to the exposed forward ends or skirt portions ofthe fragile liners typically used in such shaped charges. Similarly, ithas been found that vertical movements or jumping of the perforator toolcaused by detonation of one set of charges can also damage the metalstrips carrying the unexpended shaped charges in adjacent carriers. Ineither case, it has been found that often one or more of the shapedcharges in these adjacent carriers are sufficiently damaged that theywill not operate properly when these charges are subsequently detonated.

Accordingly, it is an object of the present invention to provide new andimproved repetitively operated shaped charge perforating apparatus whichis cooperatively arranged for protecting unfired shaped charges in theapparatus from explosive impacts or violent shocks which might otherwisedamage or disrupt these unexpended charges upon the detonation of othershaped charges in the apparatus.

This and other objects of the present invention are attained by tandemlyintercoupling upper and lower perforating guns by means of a rigid innermember which is cooperatively disposed within a rigid outer member andyieldably isolated therefrom by one or more yieldable members arrangedbetween the rigid members; with one of the guns being secured or coupledto one of these rigid members and the other gun being secured or coupledto the other rigid member. In this manner, the yieldable members betweenthe loadsupporting members will effectively isolate the two guns fromshocks developed upon actuation of the other gun. The assembly ofcoupler members is further arranged to define a protective wire passagefor carrying interconnecting electrical wires between the two guns.

The novel features of the present invention are set forth withparticularity in the appended claims. The invention, together withfurther objects and advantages thereof, may be best understood by way ofthe following description of exemplary apparatus employing theprinciples of the invention as illustrated in the accompanying drawings,in which:

FIG. 1 shows new and improved perforating apparatus arranged inaccordance with the present invention as .that apparatus is beingpositioned in a typical well bore;

FIG. 2 is an enlarged longitudinal cross-sectional view of a preferredembodiment of a new and improved shockresistant inter-carrier couplerincorporating the principles of the present invention; and

FIGS. 3 and 4 are cross-sectional views of the unique inter-carriercoupler respectively taken along the lines 3-3 and 4-4 in FIG. 2.

Turning now to FIG. 1, new and improved throughtubing perforatingapparatus 10 is shown as it is being positioned in a typical cased wellbore 11 adjacent to one of two producible earth formations 12 and 13. Asis customary, a string of small-diameter tubing 14 is suspended in thewell bore 11 and extended through a typical packer 15 set therein abovethe earth formations 12 and 13 for isolating the two producing zonesfrom that portion-of the well bore above the packer. The perforatingapparatus 10 is suspended in the usual manner from a suitable electricalcable 16 that is spooled from a winch (not shown) at the surface andconnected to the upper end of the perforating apparatus. As iscustomary, a typical casing collar locator 17 is employed for providingindications at the surface representative of the depth of theperforating apparatus 10.

Inasmuch as it is intended that the perforating apparatus 10 will besuccessively positioned opposite each of the formations l2 and 13, theperforating apparatus includes separate upper and lower guns 18 and 19which are cooperatively arranged to be individually operated uponcommand from the surface. In the preferred embodiment depicted in FIG.1, the two guns l8 and 19 are respectively arranged in accordance withthe through-tubing perforators shown in either US. Pat. No. 3,048,102 orUS. Pat. No. 3,429,384, each of which is hereby incorporated byreference. Thus, as fully described in either of the aforementionedpatents, each of the guns l8 and 19 respectively includes an enclosedcarrier 20 and 21 formed of a suitable length of thin-walled steeltubing which has a number of typical shaped explosive charges, as at 22and 23, mounted at longitudinally spaced intervals along an elongatedmetal strip (not shown) arranged therein for positioning each of thecharges for firing in a selected lateral direction. It will, of course,be appreciated that each of the guns 18 and 19 is respectively providedwith an electrically-responsive detonator (not shown) which is coupledto a length of typical detonating cord (not shown) operatively disposedalong the rear portion of each of the charges, as at 22 or 23, forsimultaneously detonating them when the detonator in that gun isenergiz'ed; 1

Since the guns l8 and 19 are to be independently fired, suitableprovisions must be made for their selective operation. Those skilled inthe art will recognize, of course, that any one of several typicalswitching arrangements may be utilized for achieving such selectivecontrol. For example, selectively operated switching systems such asthose shown in either U.S. Pat. No. 3,327,791 or US. Pat. No. 3,517,758could be successfully employedwith the new and improved perforatingapparatus of the present invention where the switching is to be directlycontrolled from the surface. Alternatively, if it is preferred that theswitching be accomplished upon firing of the lower gun 19, for example,a detonation-responsive control system, as at 24, would be included withthe new and improved perforating apparatus 10. Typicaldetonation-responsive control systems, as at 24, are fully described inUS. Pat. No. 3,246,707 and US. Pat. No. 3,246,708, each of which isincorporated herein by reference. It will, of course, be appreciatedthat since it is ordinarily preferred to shoot the lowermost gun firstand then subsequently shoot the next-higher gun, thedetonation-responsive control system 24 is operatively positionedadjacent to the upper end of the lower gun 19 so that successfuldetonation of the charges, as at 23, will electrically connect the cable16 to the detonator for the yetunexpended charges, as at 22, in theupper gun 18. Since the two last-mentioned patents fully explain theoperation of the detonation-responsive control system 24, no furtherexplanation is believed necessary. It should be realized, however, thatregardless of the control system used, electrical wires must beconnected between the upper and lower guns l8 and 19 and it is essentialto their successful operation that these wires remain undamaged at leastuntil the upper gun is fired.

The upper and lower guns l8 and 19 in the new and improved perforatingapparatus 10 are tandemly intercoupled by means of a uniquely-arrangedshock or impact-resistant inter-carrier coupler 25 which, as will besubsequently explained, is cooperatively arranged for substantiallyabsorbing the severe impact or shock forces developed upon detonation ofthe shaped charges, as at 23, in the lower gun 19 to thereby protect theyet-unfired charges, as at 22, in the upper gun 18 from unwanted damage.Thus, as best seen in FIG. 2, in its preferred embodiment the uniqueshock or impact-resistant inter-carrier 25 includes longitudinallyspacedcylindrical bodies or upper and lower heads 26 and 27 which arerespectively adapted to be complementally fitted and secured in knownangular positions within the adjacent ends of the upper and lowercarriers and 21. The upper head 26 is further provided with a dependingsupport or tubular extension 28 which is terminated by aninwardly-enlarged shoulder that, in the illustrated preferredembodiment, is provided by an externally threaded split-ring 29 sizedfor defining an upwardly facing surface as at 30. The lower head 27 is,on the other hand, provided with an upstanding support orreduced-diameter extension 31 which is coaxially disposed in thedepending extension 28 and, as best seen in FIGS. 3 and 4, terminated atits upper end by an outwardly-enlarged shoulder that is preferablyarranged as opposed lateral projections 32 and 33 that respectivelydefine downwardly-facing surfaces, as at 34, well above the upwardlyfacing surface 30.

It will, of course, be appreciated that where the switching system 24 isarranged in accordance with the aforementioned U.S. Pat. No. 3,246,707or US. Pat. No. 3,246,708, for example, the lower head 27 can also beconveniently arranged as necessary for readily supporting the componentsof such a detonationresponsive system as well as for beingcomplementally fitted and fluidly sealed within the upper end of thelower carrier 21.

As depicted in FIG. 2, the unique shock-resistant inter-carrier 25 isfurther provided with an elongated sleeve 35 of a yieldable or resilientshock-absorbing material such as a suitable elastomer, with this thicksleeve being cooperatively fitted within the annular space definedbetween the extensions 28 and 31 and engaged with the opposed shoulders30 and 34 for yieldably supporting the lower head 27 on the upper head26. To further isolate the upper and lower heads 26 and 27 against thetransmission of shock forces between the upper and lower perforatingguns 18 and 19, a second shock-absorbing member 36 is preferablyarranged between the lower head 27 and the lower face of the split-nut29 and a third shock-absorbing member 37 is disposed between the upperhead 26 and the upper faces of the shoulders 32 and 33. These additionalshock-absorbing members 36 and 37 are preferably formed of a yieldableor resilient material similar or identical to that used for the majorshock-absorbing member 35. To assure that there is a reasonable degreeof free movement between the upper and lower heads 26 and 27, theseveral shock-absorbin g members 35-37 are provided with one or moreexpansion spaces such as multiple openings or passages, as at 38 and 39,in the upper and intermediateshock-absorbing members respectively andrecesses, as at 40, in the lower shockabsorbing member.

To assure that the upper and lower heads will not become accidentallyuncoupled while the new and improved perforating apparatus 10 is beingoperated, abutments such as one or more oppositely directed threadedprojections, as at 41, are provided on the upper end of the uprightinner extension 31 and enlarged caps 42 and 43 which are coupled theretoare loosely disposed in slots, as at 44, formed in the adjacent sidewalls of the outer extension 28. In this manner, the lower surfaces ofthe opposed slots, as at 44, will define shoulders for holding theoutwardly projecting abutment caps 42 and 43 should the shockabsorbingmember 35 fail or be disintegrated while the perforating apparatus 10 isin the well bore 13. It will also be recognized that the abutment caps42 and 43 and their respectively associated slots, as at 44, willfurther serve to maintain the upper and lower heads 26 and 27 in a givenangular orientation relative to one another. This angular orientationcan, of course, be readily reversed should it'be' desired to face theshaped charges 22 in the'lop'p'osi'te' direction from the shaped charges23. v

To facilitate the necessary electrical interconnection between-the guns18 and 19,21 wire passage is provided through the inter-carrier coupler'by 'way of a-n'elongated and-somewhat-flexible tubular conduit-45 whichis coaxially disposed within the inner; extension3l and has its enlargedupper and lowerends 46 and 47 fluidly sealed within complementallyformed longitudinal passages 48 and 49 respectively arranged through theupper and lower coupling heads 26 and 27. It will be noted from FIG. .2that the passages .48 and 49 are arranged and are of.sufficient length,to accommodate the longitudinal movements :ofthe conduit45 during theuse of the new and improved inter-carrier coupler 25. Asa matter ofoperating convenience, .a lateral port 50 with a threaded plug 51 areprovided in the lower head 27 to facilitate the splicing. of theinterconneeting detonator wires (not shown) running between the two gunsl8-and 19.

It will be recogni ed, therefore, that with the upper and lower guns lSand, 1 9 being intercoup'led to one another solelyby the unique coupler2,5, the lower gun is directly conneqted totllie upper gun only by wayof the resilient members 3537. Thus, an upwardly directed shock on ,theupper gun 18 as willbe occasioned by the detonation ofthe charges, as at23, in the lower gun 19 I will besubstantially cushioned by therespective expan-- 'sion and compression of the resilient couplermembers5 -37. Similarly, since the resilient members are sufficiently yieldableunder impact for allowing the rigid coupler members 28 and 31 to tilt inrelation to one another, the resilience of the several resilient couplermembers 35-37 will effectively absorb or dampen a considerable amount ofthe laterally directed shocks or impacts which would otherwise betransmitted to the upper gun 18 when the lower gun 19 is fired. Itshould be noted at this point that although firing of the lower gun 19will impart a substantial accelerational force to the lower gun, theoperation of the inter-carrier coupler 25 will be effective for at leastminimizing or reducing the acceleration of the upper gun 18.

Accordingly, it will be appreciated that the new and improvedrepetitively operated perforating apparatus of the present invention iswell suited for guarding yetunfired shaped charges from damage as othershaped charges on the apparatus are fired. By intercoupling two or moretypical shaped charge guns with the new and improved inter-carriercoupler disclosed herein, the severe explosive shocks and excessiveaccelerational forces developed upon actuation of one of the guns in theassembled tool will be sufficiently dampened or absorbed that there willbe little or no risk of damage to the shaped charges in the other guns.

While only a particular embodiment of the present invention has beenshown and described, it is apparent that changes and modifications maybe made without departing from this invention in its broader aspects;and, therefore, the aim in the appended claims is to cover all suchchanges and modifications as fall within the true spirit and scope ofthis invention.

What is claimed is: 1. Perforating apparatus comprising: first andsecond perforating guns cooperatively arranged to be sequentiallyactuated for successively perforating spaced intervals of a well borewall; and shock-isolating means tandemly intercoupling said perforatingguns cooperatively arranged for attenuating shocks transmitted to one ofsaid perforating guns upon actuation of the other of said guns andincluding inner and outer rigid coupler members telescoped together andrespectively coupled to said first and second perforating guns, andyieldable .means cooperatively arranged between said rigid couplermembers for shock isolating said rigid coupler members'from one anotherand yieldably supporting said inner member within said outer member toaccommodate relative longitudinal and bending movements .therebetween'.

2. T h e perforating' apparatus ofclaim 1 wherein said 10 rigidconp'lermembers are tubular for defining a longitudinalpassage through each ofsaid "rigid coupler members and further including: 1 a

Tit n elongated conduit slidablymounted within said {longitudinalpassages and adapted for carrying in- 'terconne'ctingelectricalconductor means between said perforating guns. j

3,. The perforating apparatus of claim 1 further including: 1'

longitudinally-spaced opposed abutments cooperatively ar rangedon saidrigid coupler members for preventing separation of said rigidcouplermembe'rs'. f 1;" v, 4. Perforating apparatus comprisingz first and.second perforating guns cooperatively arranged for selectivelyperforating spaced intervals .ofawell bore walla v shock-isolating meansint'ercoupling I said perforating guns and including an inner memberhaving one 30 portion coupled to said first perforating gun and anotherportion thereof providing at least one outwardly projecting shoulder, anouter member having one portion coupled to said second perforating gunand another portion thereof coaxially disposed 5 around said otherportion of said inner member and having upper and lowerinwardly-projecting shoulders provided thereon which are spatiallydisposed respectively above and below said outwardly-projecting shoulderon said inner member, yieldable shock-attenuating means cooperativelyartransmitted between said perforating guns, and

conduit means cooperatively arranged through said inner and outermembers for carrying interconnecting electrical conductor means betweensaid perforating guns; and

control means cooperatively arranged for sequentially actuating saidperforating guns in succession.

5. The perforating apparatus of claim 4 wherein said yieldableshock-attenuating means include a member formed of a resilient materialengaged between said outwardly-projecting shoulder and said upperinwardly-projecting shoulder.

6. The perforating apparatus of claim 4 wherein said yieldableshock-attenuating means include a member formed of a resilient materialengaged between said outwardly-projecting shoulder and said lowerinwardlyprojecting shoulder.

7. The perforating apparatus of claim 4 wherein said yieldableshock-attenuating means include a first member formed of a resilientmaterial engaged between said outwardly projecting shoulder and saidupper inwardly projecting shoulder and a second member formed of aresilient material engaged between said outwardly projecting shoulderand said lower inwardly projecting first shock-attenuating meansincluding a first resilshoulder. ient member coaxially mounted aroundsaid re- 8. The perforating apparatus of claim 7 further induced bodyportion between said outwardly dil g: rected shoulder and one of saidinwardly directed means defining first and second normally Spaced P-shoulders for resiliently supporting one of said bod- Posed abutmentsother Portions of said ies on the other of said bodies as well asdampening mfler and outer members respectively and cooper movements ofsaid one body in one axial direction; fmvely arranged for PfeventingSeparation of Said a second shock-attenuating means including a secondmember from omer resilient member cooperatively mounted between Theperforating apparatus of claim 7 further 10 said outwardly directedshoulder and the other of cludmg: said inwardly directed shoulders forresiliently means coo erativ l r p e y at anged. p Inner dampeningmovements of said one body 1n the 0pand outer members for retaining saidinner and posite axial direction;

outer members in a fixed angular relationship with wi ass mea Xtendinthrou h Sai d first and one another without preventing relativelongitudi- 5 re p g g nal movement therebetween. secon 0 an meansco-rotatively coupling said first and second 10. Well bore apparatuscomprising: a first body adapted for coupling to a first perforatingbodies together for sl dably retaining them in a selected angularrelationship without preventing gun and including an enlargedaxially-aligned opening having upper and lower inwardly directed analmovements therebetween' h ld arranged on the walls th f; 11. The wellbore apparatus of claim 10 wherein said a second body adapted forcoupling to a second per- Wire-Passage means ineludei forati g g d i ldi a d d i ll first and second longitudinal passages respectivelyaligned portion coaxially disposed within said formed through Said firstand SeCQnd bodies, and

opening in said first body and having at least one 2 an elongatedtubular conduit slidably disposed in outwardly directed shouldercooperatively arsaid longitudinal passages and respectively extendrangedthereon and positioned between said ining between said first and secondbodies.

wardly directed shoulders;

1. Perforating apparatus comprising: first and second perforating gunscooperatively arranged to be sequentially actuated for successivelyperforating spaced intervals of a well bore wall; and shock-isolatingmeans tandemly intercoupling said perforating guns cooperativelyarranged for attenuating shocks transmitted to one of said perforatingguns upon actuation of the other of said guns and including inner andouter rigid coupler members telescoped together and respectively coupledto said first and second perforating guns, and yieldable meanscooperatively arranged between said rigid coupler members for shockisolating said rigid coupler members from one another and yieldablysupporting said inner member within said outer member to accommodaterelative longitudinal and bending movements therebetween.
 2. Theperforating apparatus of claim 1 wherein said rigid coupler members aretubular for defining a longitudinal passage through each of said rigidcoupler members and further including: an elongated conduit slidablymounted within said longitudinal passages and adapted for carryinginterconnecting electrical conductor means between said perforatingguns.
 3. The perforating apparatus of claim 1 further including:longitudinally-spaced opposed abutments cooperatively arranged on Saidrigid coupler members for preventing separation of said rigid couplermembers.
 4. Perforating apparatus comprising: first and secondperforating guns cooperatively arranged for selectively perforatingspaced intervals of a well bore wall; shock-isolating meansintercoupling said perforating guns and including an inner member havingone portion coupled to said first perforating gun and another portionthereof providing at least one outwardly projecting shoulder, an outermember having one portion coupled to said second perforating gun andanother portion thereof coaxially disposed around said other portion ofsaid inner member and having upper and lower inwardly-projectingshoulders provided thereon which are spatially disposed respectivelyabove and below said outwardly-projecting shoulder on said inner member,yieldable shock-attenuating means cooperatively arranged between saidoutwardly-projecting shoulder and at least one of saidinwardly-projecting shoulders for yieldably supporting said inner memberwithin said outer member and attenuating shocks transmitted between saidperforating guns, and conduit means cooperatively arranged through saidinner and outer members for carrying interconnecting electricalconductor means between said perforating guns; and control meanscooperatively arranged for sequentially actuating said perforating gunsin succession.
 5. The perforating apparatus of claim 4 wherein saidyieldable shock-attenuating means include a member formed of a resilientmaterial engaged between said outwardly-projecting shoulder and saidupper inwardly-projecting shoulder.
 6. The perforating apparatus ofclaim 4 wherein said yieldable shock-attenuating means include a memberformed of a resilient material engaged between said outwardly-projectingshoulder and said lower inwardly-projecting shoulder.
 7. The perforatingapparatus of claim 4 wherein said yieldable shock-attenuating meansinclude a first member formed of a resilient material engaged betweensaid outwardly projecting shoulder and said upper inwardly projectingshoulder and a second member formed of a resilient material engagedbetween said outwardly projecting shoulder and said lower inwardlyprojecting shoulder.
 8. The perforating apparatus of claim 7 furtherincluding: means defining first and second normally spaced opposedabutments on said other portions of said inner and outer membersrespectively and cooperatively arranged for preventing separation ofsaid inner member from said outer member.
 9. The perforating apparatusof claim 7 further including: means cooperatively arranged between saidinner and outer members for retaining said inner and outer members in afixed angular relationship with one another without preventing relativelongitudinal movement therebetween.
 10. Well bore apparatus comprising:a first body adapted for coupling to a first perforating gun andincluding an enlarged axially-aligned opening having upper and lowerinwardly directed shoulders arranged on the walls thereof; a second bodyadapted for coupling to a second perforating gun and including a reducedaxially aligned portion coaxially disposed within said opening in saidfirst body and having at least one outwardly directed shouldercooperatively arranged thereon and positioned between said inwardlydirected shoulders; first shock-attenuating means including a firstresilient member coaxially mounted around said reduced body portionbetween said outwardly directed shoulder and one of said inwardlydirected shoulders for resiliently supporting one of said bodies on theother of said bodies as well as dampening movements of said one body inone axial direction; a second shock-attenuating means including a secondresilient member cooperatively mounted between said outwardly directedshoulder and the other of said inwardly directed shoulders forresiliently dampening movements of said one body in the opposite axialdirection; wire-paSsage means extending through said first and secondbodies; and means co-rotatively coupling said first and second bodiestogether for slidably retaining them in a selected angular relationshipwithout preventing axial movements therebetween.
 11. The well boreapparatus of claim 10 wherein said wire-passage means include: first andsecond longitudinal passages respectively formed through said first andsecond bodies, and an elongated tubular conduit slidably disposed insaid longitudinal passages and respectively extending between said firstand second bodies.